The extensive use of various highly toxic gases in the fabrication of electronic semiconductor devices has led to the use of gas cabinets for containment of the gas cylinders. Gas cabinets are substructures for the containment of process gas cylinders within the manufacturing plant. Such cabinets provide a secure, ventilated housing to safely contain both the cylinders and the system controls. The cabinet is designed to protect the cylinders and the controls from accidental damage and also to provide a controlled access to the gas cylinders. Although not meant to be totally sealed, gas cabinets are generally designed to resist leakage of gases into the plant atmosphere.
In the event that a leak should occur within the cabinet, it is necessary that there be adequate ventilation to provide a rapid clearing of the atmosphere inside the cabinet. Thus, it is desirable that there be a complete, uniform, and continuous air sweep of the cabinet interior.
Conventional gas cabinets utilize either front or side-mounted louvers for air inlet into the cabinet and an exhaust port at the top of the cabinet. Such an arrangement can result in channeling, dead areas, and unswept corners where possible leaking gas can accumulate. The conventional method of compensating for this problem has been to connect the cabinets to very high capacity ventilation systems. Such cabinets require airflows on the order of 350 cubic feet per minute or greater for a single cylinder cabinet. Such high capacity ventilation systems are, of course, more expensive to install and maintain. Furthermore, in a plant utilizing multiple cabinets in a single room, it is possible that a partial vacuum may be created in the room such that entry to the room is hindered. Thus, it is desirable to have a gas cabinet which will provide a rapid clearing time and thorough evacuation but utilizing lower airflows.